The storm has raged since at least 1830 and possibly since the mid-1600s, when the spot may have been first seen from Earth.

"This monumental storm has raged on the solar system's biggest planet for centuries," Bolton said. "Now, Juno and her cloud-penetrating science instruments will dive in to see how deep the roots of this storm go, and help us understand how this giant storm works and what makes it so special."

NASA’s Juno probe, which stretches as wide as a basketball court, entered orbit around Jupiter one year ago. The $1-billion ship spent almost five years traveling to the giant planet, where it has been studying what lies beneath the swirling clouds.

While peering at Jupiter, Juno has learned about the planet’s origins, structure, atmosphere and magnetosphere.

The spacecraft's visit to Jupiter will be fleeting, however: In early 2018, because of the intense bombardment of radiation from the planet, Juno will go out in a blaze of glory as it takes a final dive into Jupiter's atmosphere and burns up.

Jupiter: The Basics

Namesake: King of the Roman gods.

Date of Discovery: Known to the ancients.

Orbit: Approximately 484 million miles from the sun (five times as far from the Sun as the Earth is).

Day: Approximately 10 Earth hours.

Year: Approximately 12 Earth years.

Average diameter: Approximately 88,846 miles.

Surface gravity: Approximately 2½ times Earth's.

For more information (and more precise versions of these figures), go to NASA's Solar System Exploration website's Jupiter page.